Field
The disclosure relates to a system and method for refueling a vehicle tank with liquefied petroleum (LP) gas from a storage tank using a fuel pump onboard the vehicle.
Background
LP gas is a by-product of natural gas processing and includes such fuels as propane and butane, and may also include amounts of propylene and butylene in various mixtures. As used herein, the terms “liquefied petroleum gas,” “LP gas,” and “LPG” are used interchangeably and are intended to refer to propane, butane, iso-butane, propylene, butylene, and methane, alone or in various mixtures, as well as to mixtures of other hydrocarbon gases that are stored in liquid form, under pressure, and are used as fuel for internal combustion engines.
LP gas is highly flammable and is therefore commonly used for fueling cooking and heating appliances. LP gas is also increasingly being used to power personal and commercial vehicles due to the relatively lower cost and environmental impact, as compared to conventional liquefied fuels such as gasoline or diesel.
Typically, a vehicle having an LP gas fuel system is refueled and operated similarly to other liquid fueled vehicles, such as those running on gasoline or diesel. During the refueling operation, a pump is required to move LP gas from a storage tank to a vehicle fuel tank. Unlike gasoline and diesel refueling operations, however, with LP gas, both the vehicle fuel tank and the storage tank are pressurized. A typical LP gas refueling operation is illustrated by FIGS. 1A-1B, which depict a vehicle 110 and a conventional refueling station 150. As shown by FIGS. 1A-1B, vehicle 110 includes a fuel system 120 having a connector 130 for receiving fuel from conventional refueling station 150 and a vehicle fuel tank 122 to store propane for vehicle 110. Conventional refueling station 150 includes a fuel storage tank 152 for storing LP gas, a refueling pump 156 for removing propane from storage tank 152, a pump station 154 for controlling refueling pump 156 and monitoring the flow of fuel dispensed from refueling pump 156, and a nozzle 158 for dispensing fuel into vehicle fuel tank 122 of vehicle 110.
To refuel, a user turns off an engine of vehicle 110 and connects nozzle 158 to fuel connector 130 of vehicle 110. The user then presses and holds a lever on nozzle 158, and/or activates a switch, a lever, or a button on pump station 154, to activate refueling pump 156. Once activated, refueling pump 156 pulls propane from storage tank 152 and pushes the propane to vehicle 110 via nozzle 158. Propane enters vehicle 110 by way of fuel connector 130 and then flows into fuel tank 122 via tank fill inlet 132 on fuel tank 122.
There are a number of ways that the pump station 154 terminates a refueling operation. For example, a user can stop refueling at any point be releasing the lever on nozzle 158, or pump station 154 can limit an amount of fuel based on the amount that was purchased. The pump station 154 can also stop refueling upon activation of an overfill protection device (OPD) 134 within vehicle 110. OPD 134 prevents overfilling of fuel tank 122. Typically, OPD 134 includes a float located near tank fill inlet 132 (as illustrated by FIG. 1B), or near fuel connector 130 in other examples, which rises as fuel fills fuel tank 122 and a plug that plugs tank fill inlet 132 when the float has raised to a predetermined fuel level, typically 80% of the tank level. Pump station 154 monitors the flow of fuel being dispensed to vehicle 110 such that when the flow of fuel stops (i.e., the rate of flow of the fuel is substantially zero gallons per minutes (gpm)) due to the tank fill inlet 132 being plugged by OPD 134, pump station 154 turns off refueling pump 156. After refueling has finished, the user can then disconnect nozzle 158 from fuel connector 130.
A general operation of providing fuel to an engine of vehicle 110 will now be discussed. Vehicle 110 includes a fuel pump 140 configured to pump LP gas from fuel tank 122 to an engine 146 of vehicle 110, shown in FIG. 1B. In a run operation, fuel pump 140 removes LP gas from fuel tank 122 via fuel pickup 142 which may include a fuel hose and/or a fuel filter to pickup propane from fuel tank 122. Fuel pump 140 pushes the propane to an engine fuel line 144 by way of a tank outlet 136. LP gas flows through engine fuel line 144 to engine 146 where some of the propane is injected into fuel rails 148. Unused fuel is returned to fuel tank 122 via engine fuel line 144 and a return inlet 138 of the vehicle fuel tank 122.
Ideally, fuel stations would provide LP gas to vehicles in a quick and convenient manner. However, LP gas fueling stations have limitations which discourage or hamper the more widespread adoption of LP gas use in vehicles. For example, despite the increase in popularity of LP gas vehicles and unlike conventional gas and diesel fueling stations, there are relatively few LP gas fueling stations in the United States. This means that owners of LP gas fueled vehicles are forced to either (a) drive extra distances for refueling or (b) purchase refueling pumps for installation at the customer's home or business. Customers that have a large fleet of vehicles are typically able to justify the expense of an LP gas fueling station. However, individuals with personal vehicles and companies with smaller numbers of fleet vehicles are less likely to convert to an LP gas fuel system due to the high costs of an LP gas fueling station.
What is needed is a fueling system for a vehicle that provides a method of refueling the vehicle in a safe and cost efficient manner.
The present disclosure will be described with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. Additionally, the left most digit(s) of a reference number identifies the drawing in which the reference number first appears.